This invention relates generally to exercise equipment and, more particularly, to a lubrication system for an endless belt treadmill.
Exercise treadmills are well known to the art. Generally, the exercise treadmill has deck covered by an endless belt. The user is positioned on the deck and his or her feet engage the endless bell The user walks forward and the belt moves in the opposite direction. In that manner, the user stays positioned on the deck and does not move forward. There are basically two types of endless belt conventional treadmills. In the first type, the endless belt is looped or entrained about idler rollers and covers the deck. As the user walks, he or she drives the endless belt about the rollers and deck. In the second type, the endless belt is entrained about and driven by a motorized drive roller, for example. The speed at which the belt moves may be variable. In any event,the user stands on the belt on the support deck facing forward and belt is driven backward, relative to the user. The user then is forced to walk forward on the belt to maintain position. Either type of treadmill may have additional features such as devices to exercise the upper torso, computers, timers and so forth.
Whether the treadmill employs a user driven belt or a motor driven belt, when the user's foot impacts the belt surface, the belt presses against the deck causing friction between the belt and deck. Such friction reduces belt life and can impede smooth operation of the endless bell. In treadmills using motor driven belts, the friction places additional stress on the drive system. This results in additional power consumption and heat generation.
Treadmill builders have attempted to minimize the effects of belt to deck friction by waxing the treadmill deck or the inner surface of the belt prior to assembly of the treadmill. For example, the manufacturer can manually rub wax on the inner belt surface. Furthermore, the manufacturer could embed solid wax particles in the belt. U.S. Pat. No. 3.659,845, to Quinton, discloses a treadmill having an endless belt impregnated with wax.
As shown in U.S. Pat. No. 3,703,284, to Hesen, treadmill constructions are known in which a heavy, multi-ply nylon belt is driven along a metal bedplate, with the bedplate being composed of a high heat conductivity material (e.g. a metal plate) which in turn is coated with a Teflon coating so as to result in low friction between the moving belt and the bed plate. However, as admitted in the patent, the Teflon coating applied to the metal bed tended to wear from the metal plate with a consequent rise in the coefficient of friction between the belt and the plate resulting in temperature increases for the belt.
It will be appreciated, therefore, that despite the manufacturing method employed, wax or lubricant applied at the time of assembly dissipates as the treadmill is used. While an initial waxed belt to deck coefficient of friction may be 0.2, this number increases as treadmill use increases. Eventually, after about 600 hours of use, the belt to deck coefficient of friction rises to approximately 0.4. An acceptable coefficient of friction to maintain the serviceability of the belt is approximately 0.2 to 0.3.
The servicing of treadmills is a particularly important concern in heavy use applications such as health clubs. In a health club setting a single treadmill may operate nearly continuously for eight to twelve or more hours a day. The continuous operation causes a noticeable decrease in performance after 200 to 300 hours of use. If the treadmill is neglected, it can fail after 600 to 1000 hours of service.
Various mechanism for applying a lubricant to the inner surface of the endless belt have been tried. For example, U.S. Pat. No. 5,433,679 to Szymczak et al, provides a lubrication system that requires sophisticated pumps to apply the lubricant. Furthermore, a monitoring circuit is employed to monitor the application of lubricant. Such devices add expense to the construction and are prone to nozzle blockage and failure. Reference also may be made to U.S. Pat. No. 4,344,616, which may be relevant to the instant invention.
It is desirable, therefore, to have a treadmill that has minimal belt to deck friction so as to avoid wear and failure. Moreover, it is desirable to have such a treadmill that extends the length of time between servicing and thereby decreases down time. Such a treadmill should employ a relatively simple means for applying a lubricant to the inner surface of the endless belt to decrease the coefficient of friction between the belt and the deck.